1. Field of the Invention
The present invention relates generally to golf swing training devices. More particularly, the invention concerns a machine for conveying to a trainee the differences between two putter swing methods, namely the “inward” swing method and the “outward” swing method.
2. Discussion of the Prior Art
It is generally agreed that there are two mutually exclusive and equally effective optimum golf swings, namely the so-called “inward” golf swing and the so-called “outward” golf swing. It is also generally agreed that the golf swing embodies two separate applications of geometry, both of which must be properly addressed in an effective golf swing. The first of these, namely “Impact geometry” concerns the fact that one must compress the ball on the face of the club head in such a manner that maximum swing force is transferred. Accomplishing this without side spin is the ideal, but most accomplished golfers use either a draw spin or a fade spin in carrying out the majority of their shots.
The other application of geometry, namely “force controlling geometry,” produces the physics that controls the transfer of the total swing force to the club head. Most good golfers develop a feel for an effective swing through a trial and error method (“muscle memory”) that is inconsistent at best. Adding to the difficulty with this approach is the fact that there are two diametrically opposed procedures for effectively releasing the club head, each with its own unique feel. Mostly because of this fact, contradictory advice has always plagued the game; more often by being incomplete, rather than totally wrong.
The forgoing and various other theories concerning the golf swing have been discussed in numerous books and articles, including books by Ben Hogan and Horner Kelley.
Ben Hogan in his noted work, Five Lessons: The Modern Fundamentals of Golf likened the swing plane to a large flat pane of glass inclined from the intended line of flight of the ball and generally resting on the shoulders of the trainee. In Hogan's theory, the glass pane intersected the ground in a line which was coincident with the line of flight. To control club movement, the golfer ideally swung the club head underneath the plane throughout the swing. However, Hogan introduced a slight shift in the plane line in the downswing to account for the apparent motion of the club head outward and away from the golfer from hip height through impact.
Horner Kelley in his well known book The Golfing Machine describes the swing plane as a two dimensional geometric structure on which the entire club moves throughout the golf swing. Kelley pictured the swing plane as a flat pane of glass intersecting the ground in a line, with the plane line being identical with the intended initial line of flight of the ball. This plane was described by Kelley as having a dynamically changing inclined angle during the swing with the entire club remaining on the plane throughout the swing.
Kelley mentions in his book that, depending on the number of accumulators used, that is, parts of his “power package”, a golf swing can be anything from a simple “one barrel” to a full “four barrel” version.
The inward and outward swings, which are taught to be recognized by the trainee through the use of the apparatus of the present invention, can be explained in terms of the Kelley concepts as follows: Basically there are five basic elements of the golf swing, the lower body (hips), the upper body (shoulders), the leading arm, the hands, and the shaft flex. These five elements are released in the sequence listed in the downswing of each swing method. However, each element has the potential to release in either direction, that is, inward or outward. As such, they have the capacity to create torque four times by opposing each other in sequential fashion. It is these four potential segments of torque that actually establish the number of barrels a swing contains and, thereby, its ability to create effortless power.
In performing the golf swing, each of the five basic elements of the golf swing is indirectly affected by each of the others. For example, the hips are outward when they are adding to the turning force of the swing through impact and they are inward when they are resisting this force. The shoulders act similarly, but must act in an opposite direction to the hips for a four barrel swing to result. The leading arm is outward when the angle formed by it and the shoulders is increasing (Kelley's #4 accumulator); and it is inward when this angle is decreasing through impact. The action of the hands and club shaft are similar to the action of the hips and shoulders.
The importance of understanding and being able to recognize the two swing methods discussed in the preceding paragraphs is highlighted by the fact that, while most touring professionals are inward swingers there are some notable exceptions, including Jack Nicklaus, Greg Norman, Fred Couples and John Daly. Examples of renowned inward swingers include Arnold Palmer, Lee Trevino, Steve Ellington and Nick Faldo.
Teachers of golf and authors of books and articles on the golf swing almost always fall into one category or the other. For example, Ben Hogan's Five Lessons, The Modern Fundamentals of Golf tends to favor the inward swing, while Leslie King's Master key to Good Golf tends to favor the outward swing.